Proofs
Proofs. Bogus “Proof” that 2 = 4. Let x := 2, y := 4, z := 3 Then x+y = 2z Rearranging, x-2z = -y and x = -y+2z Multiply: x 2 -2xz = y 2 -2yz Add z 2 : x 2 -2xz+z 2 = y 2 -2yz+z 2 Factor: (x-z) 2 = (y-z) 2 Take square roots: x-z = y-z So x=y, or in other words, 2 = 4. ???.
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